//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).

#include "db/event_helpers.h"

namespace rocksdb {

namespace {
template<class T>
inline T SafeDivide(T a, T b) {
  return b == 0 ? 0 : a / b;
}
}  // namespace

void EventHelpers::AppendCurrentTime(JSONWriter* jwriter) {
  *jwriter << "time_micros"
           << std::chrono::duration_cast<std::chrono::microseconds>(
                  std::chrono::system_clock::now().time_since_epoch()).count();
}

#ifndef ROCKSDB_LITE
void EventHelpers::NotifyTableFileCreationStarted(
    const std::vector<std::shared_ptr<EventListener>>& listeners,
    const std::string& db_name, const std::string& cf_name,
    const std::string& file_path, int job_id, TableFileCreationReason reason) {
  TableFileCreationBriefInfo info;
  info.db_name = db_name;
  info.cf_name = cf_name;
  info.file_path = file_path;
  info.job_id = job_id;
  info.reason = reason;
  for (auto& listener : listeners) {
    listener->OnTableFileCreationStarted(info);
  }
}
#endif  // !ROCKSDB_LITE

void EventHelpers::NotifyOnBackgroundError(
    const std::vector<std::shared_ptr<EventListener>>& listeners,
    BackgroundErrorReason reason, Status* bg_error,
    InstrumentedMutex* db_mutex) {
#ifndef ROCKSDB_LITE
  if (listeners.size() == 0U) {
    return;
  }
  db_mutex->AssertHeld();
  // release lock while notifying events
  db_mutex->Unlock();
  for (auto& listener : listeners) {
    listener->OnBackgroundError(reason, bg_error);
  }
  db_mutex->Lock();
#endif  // ROCKSDB_LITE
}

void EventHelpers::LogAndNotifyTableFileCreationFinished(
    EventLogger* event_logger,
    const std::vector<std::shared_ptr<EventListener>>& listeners,
    const std::string& db_name, const std::string& cf_name,
    const std::string& file_path, int job_id, const FileDescriptor& fd,
    const TableProperties& table_properties, TableFileCreationReason reason,
    const Status& s) {
  if (s.ok() && event_logger) {
    JSONWriter jwriter;
    AppendCurrentTime(&jwriter);
    jwriter << "cf_name" << cf_name << "job" << job_id << "event"
            << "table_file_creation"
            << "file_number" << fd.GetNumber() << "file_size"
            << fd.GetFileSize();

    // table_properties
    {
      jwriter << "table_properties";
      jwriter.StartObject();

      // basic properties:
      jwriter << "data_size" << table_properties.data_size << "index_size"
              << table_properties.index_size << "filter_size"
              << table_properties.filter_size << "raw_key_size"
              << table_properties.raw_key_size << "raw_average_key_size"
              << SafeDivide(table_properties.raw_key_size,
                            table_properties.num_entries)
              << "raw_value_size" << table_properties.raw_value_size
              << "raw_average_value_size"
              << SafeDivide(table_properties.raw_value_size,
                            table_properties.num_entries)
              << "num_data_blocks" << table_properties.num_data_blocks
              << "num_entries" << table_properties.num_entries
              << "filter_policy_name" << table_properties.filter_policy_name;

      // user collected properties
      for (const auto& prop : table_properties.readable_properties) {
        jwriter << prop.first << prop.second;
      }
      jwriter.EndObject();
    }
    jwriter.EndObject();

    event_logger->Log(jwriter);
  }

#ifndef ROCKSDB_LITE
  if (listeners.size() == 0) {
    return;
  }
  TableFileCreationInfo info;
  info.db_name = db_name;
  info.cf_name = cf_name;
  info.file_path = file_path;
  info.file_size = fd.file_size;
  info.job_id = job_id;
  info.table_properties = table_properties;
  info.reason = reason;
  info.status = s;
  for (auto& listener : listeners) {
    listener->OnTableFileCreated(info);
  }
#endif  // !ROCKSDB_LITE
}

void EventHelpers::LogAndNotifyTableFileDeletion(
    EventLogger* event_logger, int job_id,
    uint64_t file_number, const std::string& file_path,
    const Status& status, const std::string& dbname,
    const std::vector<std::shared_ptr<EventListener>>& listeners) {

  JSONWriter jwriter;
  AppendCurrentTime(&jwriter);

  jwriter << "job" << job_id
          << "event" << "table_file_deletion"
          << "file_number" << file_number;
  if (!status.ok()) {
    jwriter << "status" << status.ToString();
  }

  jwriter.EndObject();

  event_logger->Log(jwriter);

#ifndef ROCKSDB_LITE
  TableFileDeletionInfo info;
  info.db_name = dbname;
  info.job_id = job_id;
  info.file_path = file_path;
  info.status = status;
  for (auto& listener : listeners) {
    listener->OnTableFileDeleted(info);
  }
#endif  // !ROCKSDB_LITE
}

}  // namespace rocksdb
